4 files changed, 50 insertions, 1 deletions

diff --git a/src/corelib/thread/qfutureinterface.h b/src/corelib/thread/qfutureinterface.h
index bcdae24833..e4cc46e929 100644
--- a/src/corelib/thread/qfutureinterface.h
+++ b/src/corelib/thread/qfutureinterface.h
@@ -201,7 +201,7 @@ inline void QFutureInterface<T>::reportResult(const T *result, int index)
     if (store.filterMode()) {
         const int resultCountBefore = store.count();
         store.addResult<T>(index, result);
-        this->reportResultsReady(resultCountBefore, resultCountBefore + store.count());
+        this->reportResultsReady(resultCountBefore, store.count());
     } else {
         const int insertIndex = store.addResult<T>(index, result);
         this->reportResultsReady(insertIndex, insertIndex + 1);
diff --git a/src/corelib/thread/qorderedmutexlocker_p.h b/src/corelib/thread/qorderedmutexlocker_p.h
index 83edfd5879..9a9aaefa02 100644
--- a/src/corelib/thread/qorderedmutexlocker_p.h
+++ b/src/corelib/thread/qorderedmutexlocker_p.h
@@ -74,6 +74,28 @@ public:
     {
         relock();
     }
+
+    Q_DISABLE_COPY(QOrderedMutexLocker)
+
+    void swap(QOrderedMutexLocker &other) noexcept
+    {
+        qSwap(this->mtx1, other.mtx1);
+        qSwap(this->mtx2, other.mtx2);
+        qSwap(this->locked, other.locked);
+    }
+
+    QOrderedMutexLocker  &operator=(QOrderedMutexLocker &&other) noexcept {
+        QOrderedMutexLocker moved(std::move(other));
+        swap(moved);
+        return *this;
+    }
+
+    QOrderedMutexLocker(QOrderedMutexLocker &&other) noexcept
+        : mtx1(std::exchange(other.mtx1, nullptr))
+        , mtx2(std::exchange(other.mtx2, nullptr))
+        , locked(std::exchange(other.locked, false))
+    {}
+
     ~QOrderedMutexLocker()
     {
         unlock();
@@ -88,6 +110,21 @@ public:
         }
     }
 
+    /*!
+        \internal
+        Can be called if the mutexes have been unlocked manually, and sets the
+        state of the QOrderedMutexLocker to unlocked.
+        The caller is expected to have unlocked both of them if they
+        are not the same. Calling this method when the QOrderedMutexLocker is
+        unlocked or when the provided mutexes have not actually been unlocked is
+        UB.
+     */
+    void dismiss()
+    {
+        Q_ASSERT(locked);
+        locked = false;
+    }
+
     void unlock()
     {
         if (locked) {
@@ -153,11 +190,15 @@ private:
 class QOrderedMutexLocker
 {
 public:
+    Q_DISABLE_COPY(QOrderedMutexLocker)
     QOrderedMutexLocker(QBasicMutex *, QBasicMutex *) {}
+    QOrderedMutexLocker(QOrderedMutexLocker &&) = default;
+    QOrderedMutexLocker& operator=(QOrderedMutexLocker &&other) = default;
     ~QOrderedMutexLocker() {}
 
     void relock() {}
     void unlock() {}
+    void dismiss() {}
 
     static bool relock(QBasicMutex *, QBasicMutex *) { return false; }
 };
diff --git a/src/corelib/thread/qresultstore.cpp b/src/corelib/thread/qresultstore.cpp
index 0b82b938e1..069e2a7a07 100644
--- a/src/corelib/thread/qresultstore.cpp
+++ b/src/corelib/thread/qresultstore.cpp
@@ -185,6 +185,7 @@ int ResultStoreBase::addResult(int index, const void *result)
 int ResultStoreBase::addResults(int index, const void *results, int vectorSize, int totalCount)
 {
     if (m_filterMode == false || vectorSize == totalCount) {
+        Q_ASSERT(vectorSize != 0);
         ResultItem resultItem(results, vectorSize);
         return insertResultItem(index, resultItem);
     } else {
diff --git a/src/corelib/thread/qresultstore.h b/src/corelib/thread/qresultstore.h
index 7a65089396..f58341cdf0 100644
--- a/src/corelib/thread/qresultstore.h
+++ b/src/corelib/thread/qresultstore.h
@@ -151,12 +151,19 @@ public:
     template <typename T>
     int addResults(int index, const QVector<T> *results)
     {
+        if (results->empty()) // reject if results are empty
+            return -1;
+
         return addResults(index, new QVector<T>(*results), results->count(), results->count());
     }
 
     template <typename T>
     int addResults(int index, const QVector<T> *results, int totalCount)
     {
+        // reject if results are empty, and nothing is filtered away
+        if ((m_filterMode == false || results->count() == totalCount) && results->empty())
+            return -1;
+
         if (m_filterMode == true && results->count() != totalCount && 0 == results->count())
             return addResults(index, nullptr, 0, totalCount);
         else